Many public and private groups, such as security and safety personnel (e.g., police, fire fighters and ambulance drivers) use various communication networks of differing technologies and types for communication. Many networks utilize land mobile radios communicating through push-to-talk technologies. However, communications among different endpoints of different networks such as endpoints of different police, fire or other security networks may be difficult. Collaboration between the different agencies and networks tends to be ad hoc and inefficient. When achieved, it often involves laborious manual intervention. Organizations working towards interoperability solutions include Raytheon JPS Communications, IP Blue, Twisted Pair, M/A-COM, Motorola and Cisco Systems.
In addition, many networks of public and private groups, such as security and safety personnel, utilize push-to-talk technology to enable communications among members of a particular group. Groups members may communicate using push-to-talk endpoints, such as land mobile radios. These endpoints are typically half duplex endpoints such that they cannot support both outgoing and incoming communications at one time.